Corns and calluses
Feet undergo repetitive friction and pressure, causing the numbers of basal epidermal cells (keratinocytes) to increase and the stratum corneum to thicken to protect the skin. Callus (tyloma) forms which can sometimes be painful and crack, with risk of secondary infection, requiring treatment. Sometimes callus develops a hard round mass of keratinocytes at the centre forming a corn (heloma), which may press on the deeper layers and be painful. Ill-fitting shoes, excess walking or athletics over the years may lead to changes that usually occur over bony prominences such as the ball of the foot, prominent toes and bony abnormalities such as bunions, hammer toes. This patient with extensive callus formation had a club foot. Mild problems may be helped by soaking in warm soapy water, moisturisers, sometimes with 10-20% urea to soften the lesions and attention to footwear. More severe cases can be helped by a podiatist paring the lesions, chemical treatment with a keratolytic, footpads and toe protection, and assessment of the need for surgery to correct underlying bony abnormalities.